joseph-thomas_a.ppt by wanghonghx

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									              ECE5320 Mechatronics
Assignment#01: Literature Survey on Sensors and Actuators

               Topic: Molecular Motor


                      Prepared by:
                     Joseph Thomas
     Dept. of Electrical and Computer Engineering
                  Utah State University
   E: (435)757-7962 ; T: (435)797-; F: (435)797-3054
                       (ECE Dept.)
                        3/6/2009
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                                   Outline
       –    Reference list
       –    To probe further
       –    Major applications
       –    Basic working principle illustrated
       –    A typical sample configuration in application
            (application notes)
       –    Limitations




6/27/2011           ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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                         Reference list
  • A Reversible, Unidirectional Molecular Rotary Motor Driven by
    Chemical EnergyStephen P. Fletcher, Frédéric Dumur, Michael M.
    Pollard, and Ben L. Feringa (7 October 2005) Science 310 (5745)
  • Nanoscale Rotary Motors Driven by Electron Tunneling Boyang
    Wang, Lela Vukovic, and Petr Kral, Phys. Rev. Lett. 101, 186808
    (2008)
  • Chemically Tunable Nanoscale Propellers of Liquids Boyang
    Wang and Petr Kral, Phys. Rev. Lett. 98, 266102 (2007)




6/27/2011          ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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               To explore further
    (survival pointers of web references etc)
  • http://www.chemistry.illinois.edu/research/organic/seminar_extrac
    ts/2002_2003/Quinn.pdf
  • http://www.sciencemag.org/cgi/content/abstract/310/5745/80
  • http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal
    &id=JCPSA6000123000018184702000001&idtype=cvips&gifs=y
    es




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                   Major applications
  • The assembly of a molecular propeller and a molecular motor can
    form a nanoscale machine that can pump fluids or perform
    locomotion. Future applications of these nanosystems range from
    novel analytical tools in physics and chemistry, drug delivery and
    gene therapy in biology and medicine, advanced nanofluidic lab-
    on-a-chip techniques, to tiny robots performing various activities
    at the nanoscale or microscale.




6/27/2011          ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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       Basic working principle illustrated
  Chemically driven rotary molecular motors




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       Basic working principle illustrated
  Chemically driven rotary molecular motors
       The system is made up from a three-bladed triptycene rotor and a
       helicene, and is capable of performing a unidirectional 120°
       rotation.This rotation takes place in five steps. First,
       the amine group present on the triptycene moiety is converted to
       an isocyanate group by condensation with a phosgene molecule
       (a). Thermal or spontaneous rotation around the central bond then
       brings the isocyanate group in proximity of the hydroxyl group
       located on the helicene moiety (b), thereby allowing these two
       groups to react with each other (c).



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       Basic working principle illustrated
  Chemically driven rotary molecular motors
      This     reaction     irreversibly    traps     the   system     as
      a strained cyclicurethane that is higher in energy and thus
      energetically closer to the rotational energy barrier than the
      original state. Further rotation of the triptycene moiety therefore
      requires only a relatively small amount of thermal activation in
      order to overcome this barrier, thereby releasing the strain (d).
      Finally, cleavage of the urethane group restores the amine and
      alcoholfunctionalities of the molecule (e).




6/27/2011            ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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       Basic working principle illustrated
  Light-driven rotary molecular motors




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       Basic working principle illustrated
  Light-driven rotary molecular motors
        The 360° molecular motor system consists of a bis-helicene
        connected by an alkene double bond displaying axial chirality
        and having two stereocenters.One cycle of unidirectional rotation
        takes 4 reaction steps. The first step is a low temperature
        endothermic photoisomerization of the trans (P,P) isomer 1 to the
        cis (M,M) 2 where P stands for the right-handed helix and M for
        the left-handed helix. In this process, the two axial methyl groups
        are converted into two less sterically favorable equatorial methyl
        groups.



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       Basic working principle illustrated
  Light-driven rotary molecular motors
        By increasing the temperature to 20 °C these methyl groups
        convert back exothermally to the (P,P) cis axial groups (3) in a
        helix inversion. Because the axial isomer is more stable than the
        equatorial isomer, reverse rotation is blocked. A second
        photoisomerization converts (P,P) cis 3 into (M,M) trans 4, again
        with accompanying formation of sterically unfavorable equatorial
        methyl groups. A thermal isomerization process at 60 °C closes
        the 360° cycle back to the axial positions.




6/27/2011            ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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       Basic working principle illustrated
  Light-driven rotary molecular motors




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       Basic working principle illustrated
  Light-driven rotary molecular motors
       Another example of synthetic chemically driven rotary molecular
       motor that has been reported in literature make use of the
       stereoselective ring opening of a racemic biaryl lactone by the
       use of chiral reagents, which results in a directed 90° rotation of
       one aryl with respect to the other aryl. Feringa and co-workers
       used this approach in their design of a molecule that can
       repeatably perform 360° rotation. The full rotation of this
       molecular motor takes place in four different stages.




6/27/2011            ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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       Basic working principle illustrated
  Light-driven rotary molecular motors
        In stages A and C, rotation of the aryl moiety is restricted,
        although helix inversion is possible. In stages B and D, the aryl
        can rotate with respect to the naphthalene, however, steric
        interactions do prevent the aryl from passing the naphthalene.
        The rotary cycle consists of four chemically induced steps which
        realize the conversion of one stage into the next. Steps 1 and 3
        are asymmetric ring opening reactions which make use of a chiral
        reagent in order to control the direction of the rotation of the aryl.
        Steps 2 and 4 consist of the deprotection of the phenol, followed
        by regioselective ring formation. So far, this molecular motor is
        the only reported example of a fully chemically driven artificial
        rotary molecular motor that is capable of 360° rotation.
6/27/2011             ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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       Basic working principle illustrated
  Electron tunneling driven rotary molecular motors




6/27/2011      ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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       Basic working principle illustrated
  Electron tunneling driven rotary molecular motors
       As shown in the figure above, one type of motor has a shaft
       formed by a (12,0) carbon nanotube, which could be fixed into
       CNT bearings. Three (six) stalks, formed by polymerized iceane
       molecules with saturated bonds are attached to the shaft at an
       angle of 120° (60°) with respect to each other. The stalks are
       chosen to have the length of 2 nm, in order to prevent
        nonresonant electron tunneling from the blades to the shaft.




6/27/2011             ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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       Basic working principle illustrated
  Electron tunneling driven rotary molecular motors
        The energies of their electronic states should also prevent the
        electron transfer along the stalks by resonant tunneling. The
        blades are formed by molecules with conjugated bonds
        (fullerenes), covalently attached at the top of the stalks. In
        principle, such a hybrid molecular rotor could be synthesized by
        cycloaddition reactions.




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       Basic working principle illustrated
  Molecular propeller




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       Basic working principle illustrated
  Molecular propeller
        The molecular propellers designed in the group of Prof. Petr Král
        from the University of Illinois at Chicago have their blades
        formed by planar aromatic molecules and the shaft is a carbon
        nanotube. Molecular dynamics simulations show that these
        propellers can serve as efficient pumps in the bulk and at the
        surfaces of liquids. Their pumping efficiency depends on the
        chemistry of the interface between the blades and the liquid.




6/27/2011            ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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       Basic working principle illustrated
  Molecular propeller
        For example, if the blades are hydrophobic, water molecules do
        not bind to them, due to their little bond polarity, and the
        propellers can pump them well. If the blades are hydrophilic,
        water molecules form hydrogen bonds with the atoms in the
        polar blades. This can largely block the flow of other water
        molecules around the blades and significantly slow down their
        pumping.




6/27/2011            ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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       Basic working principle illustrated
  Molecular propeller
       Molecular propellers can be rotated by molecular motors that can
       be driven by chemical, biological, optical and electrical means or
       various ratchet-like mechanisms. Nature realizes most biological
       activities with a large number of highly sophisticated molecular
       motors, such as myosin, kinesin, and ATP synthase. For
       example, rotary molecular motors attached to protein-based tails
       called flagella can propel bacteria.




6/27/2011            ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators
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                             Limitations
  • Molecular motors and propellers are in a research and
    development face hence they are far from commercially useful.




6/27/2011          ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

								
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